Rig-o-berto

my darling, 

you will never be unloved by me, 

you are too well tangled in my soul - atticus

These photos show the embryonic form of Limulus polyphemus, commonly known as the Atlantic horseshoe crab. The eggs of this species are initially opaque, with a grayish-blue, green, or pink coloration, but they become increasingly translucent as the embryos mature, providing a glimpse of the tiny horseshoe crabs developing within.

Above: several embryos twirling around in their eggs

The legs become visible roughly five days after fertilization, and the embryos begin to move shortly thereafter, eventually flexing their legs and twirling their bodies. They molt for the very first time just a few days later. Each embryo will shed its skin and grow a new one four times in total before it even hatches from the egg.

The color variations are likely related to the growth rate of each individual embryo, which can differ slightly based on the temperature, salinity, moisture, and oxygen levels around each egg. Certain colors can also arise from bacterial or fungal growth in the egg membrane.

Above: Limulus polyphemus embryos

The hatchlings finally emerge after 2-4 weeks. The freshly-hatched larvae measure less than 1cm long, and they look just like miniature versions of their adult form, except that they do not yet have tails (which are actually known as telsons) and their exoskeletons are still soft and translucent. These young horseshoe crabs are often described as "trilobite larvae."

Above: a young horseshoe crab discarding its egg

Atlantic horseshoe crabs generally spawn in May and June, with hundreds of thousands of individuals gathering along the coast on the night of the full moon and new moon. Each female lays up to 100,000 eggs per season, but very few of those offspring actually survive to adulthood. Most of the eggs are eaten or destroyed before they can even hatch, and many of the remaining larvae perish at some point during the 10 years that it takes for them to reach full maturity (i.e. the age at which they begin to reproduce).

Above: the freshly-hatched larvae

Wild horseshoe crabs can live to be more than 20 years old, and they can measure up to 60 centimeters (2 feet) long. They have 10 eyes in total, including two compound eyes that are specifically adapted for the purpose of finding a mate:

The most obvious eyes are the two lateral compound eyes. These are used for finding mates during the spawning season. Each compound eye has about 1,000 receptors or ommatidia. The cones and rods of the lateral eyes have a similar structure to those found in human eyes, but are around 100 times larger in size. At night, the lateral eyes are chemically stimulated to greatly increase the sensitivity of each receptor to light. This allows the horseshoe crab to identify other horseshoe crabs in the darkness.

Above: a close-up of a horseshoe crab's compound eye, which is covered in tiny hatchlings for some reason

Horseshoe crabs have been around for at least 445 million years, which means that these creatures are about 200 million years older than the dinosaurs and at least 50 million years older than trees, and yet their morphology has changed very little in that time. In fact, modern horseshoe crabs are frequently described as "living fossils," because they still look strikingly similar to their fossilized ancestors.

Above: the juvenile form of Tachypleus tridentatus, commonly known as the Chinese horseshoe crab

It's important to note that horseshoe crabs are not true crabs. In fact, they're not even crustaceans -- they belong to a completely different group of arthropods known as chelicerates, and they are more closely related to spiders and scorpions than they are to crabs.

Above: Tachypleus tridentatus and Limulus polyphemus

This is a revised/updated version of a post that I published about two years ago, with much more information, photos, and sources.

Sources & More Info:

iNaturalist: Horseshoe Crab Eggs

Maryland Department of Natural Resources: Horseshoe Crab Life History

Current Zoology: Developmental Ecology of the American Horseshoe Crab

PBS: Once a Spawn a Time: Horseshoe Crabs Mob the Beach

Smithsonian National Zoo and Conservation Biology Institute: Limulus polyphemus

National Wildlife Federation: Horseshoe Crabs

aquarium /

animated version on my insta! -

Usually he is quite a patient man. One must be with the dead.

But this is trying even his good will. .

“Rook we have been to three different blacksmith shops this morning alone,” he protests as Rook veers to the left where a sign promises “Genuine Dragon Hide Hilt Wraps!”

Lucanis does not help. Lucanis’s eyes light up more than Spite’s and he follows Rook with the anticipation of a much younger person spotting candy.

Rather than be dragged after them, Emmrich releases Rook’s hand, and sighs as Rook answers his protest with a weak, “Just one more, Em. Promise.”

And so he finds a shaded fountain to sit beside. And he waits.

He is only there a short while when a woman, surrounded by a small brood of excited children settles beside him, sets down numerous bags of shopping.

“You don’t mind, do you love?” she says, with the unabashed openness of most of the people of Rivain. “This road is murder on my feet.”

It takes Emmrich half a moment to realise she is addressing him and not one of the half dozen, chattering urchins bouncing around her.

“Oh, not at all, please,” Emmrich motions to the public fountain into which two of the children have already climbed.

“A hot day,” she says conversationally, “but there’s so much to do, and the weather waits for no man, nor woman.”

“Indeed,” Emmrich concedes, glancing up at the punishing sun. He’s grateful now that Taash insisted he cake himself in the cream meant to protect one’s skin from burning.

Her children play for a few moments as she fans herself and they watch the lively activity.

“Do you have any little ones?” she asks.

Manfred, immediately springs to mind. He is spending the day with Bellara, examining the artifacts they gathered from Arlathan last week. No doubt they are elbow bone deep in cogs by now.

The woman see’s Emmrich’s reminiscent smile, “tell me of them.”

By the time Rook and Lucanis wander from the shop, clutching their purchases, they are anticipating at the very least a disapproving tut, and maybe some foot tapping.

Instead they find a smiling Emmrich, surrounded by a dozen entranced children, watching the little dragon he has created from water fly in the air, running and shrieking when it sprays them. No less than four grateful parents are soaking their feet in the fountain.

“Gods, he’s cute,” Rook says and hurries off to that fruit seller Emmrich likes. It’s almost lunchtime and he’ll be hungry after an audience like this.

The Alchymist, in Search of the Philosopher's Stone, Discovers Phosphorus, and prays for the successful Conclusion of his operation, as was the custom of the Ancient Chymical Astrologers

Designs i did at the beginning of the year for @/alice_designs_12's (ig) card game, Brew & Breaker :)

School For Dragon Babies (1884) + Seminary For More Advanced Dragon Babies (1892)