254 



THE AM EH IC AN NATURALIST [A^ol. XLI 



By April 17 the eggs had become coated over with a dark deposit, 

 but the embrv^o within was far advanced and easily escaped when 

 pressure caused the egg case to spring open. With Zeiss 2. A. it 

 was evident that the embryo was clothed in a loose cuticle, or cast 

 off shell, which loosely invested the tips of the first and second 

 antennae, the chelae, the walking-legs, the abdomen and thorax as 

 well as the ends of the gills when torn out of the gill chamber. 



These embryos were now essentially the same as when they 

 hatched three days later. The eyes were almost sessile and with 

 the pigment restricted to a narrow (lescetit and this pigment 

 reflected yellow light but appeartMl black by ti-ansmitted light. 

 The yolk was still a large dark mass of sa(l(II<"-l)ag shape. The 

 tips of the fourth and fifth legs were strangely bent back like 

 hooks while the tips of the claws of the chelae did not as yet seem 

 to be recurved. All over the body the extremely dark crimson 

 pigment cells again emphasized the agreement of embryo and 

 parent in intensity of coloration. 



But the detail of anatomy of the telson was the most important 

 character for understanding the subsequent attachment of the 

 young to the parent. The abdomen ended in a simple, flat, 

 rounded telson that bore a row of simple spines along its posterior 

 edge as seen with 2. D. in figure 3. The spines were fourteen or 

 fifteen on each side symmetrically placed right and left, and a 

 group of seven or eight of them on each sifle, near the median 

 plane, seemed to push off the loose cuticle, which on the middle 

 plane, was close to the body. The spines, or better, papillae, 

 were highly refractive and clear except that some showed granules 

 and some vacuoles in their homogeneous contents. Some of them 

 had small protrusions at the tips as if paste-like material had 

 extruded from within. 



arched <.ln-, mvx and J-cnicd o,-oJn tojjcthcr. On the aninml's 

 left tlic >pinrs 7 and 1 1 wen- -rown toovthcr at their tips while S 



ami th.- >anH- was true of and 12. 'with hiuhrr [.owrr, I nun. 

 4.45 conip. oc, tnfts of fine threa-ls, or hbrils w<t.- x-en .hvrrpn*: 

 from the tips of many s])ines to pass, posttMiorly, often beyond 

 the tips of other spines. Some of the.se threads passed ont to the 



