34 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxi. 



fig. 2<?, and shows a rather more advanced stage, although it comes 

 very close to Sars's figure, and differs considerably from the epimeral 

 plate of larger specimens. Sars's figure is about intermediate between 

 my figures 2b and 2c, representing specimens of 55 and 68 mm., 

 respectively. 



Sex in G. calcarata. — It is rather hard to distinguish male and 

 female in this genus unless full-grown individuals are at hand. Old 

 females are readil} r recognized by the presence of marsupial lamellae 

 at the bases of the thoracic legs. These lamellae ''are absent in the 

 male, but the male has, at the coxa of the last pair of legs, posteriorly 

 and on each side, a small tuberculiform prominence, representing the 

 outer sexual appendage." 



In young and not quite adult females, however, the marsupial 

 lamelhe are comparatively small. In all the females of the present 

 species, even the largest, the lamelhe were not fully developed, being 

 short and narrow, not folding over one another in the median line, so 

 that a "marsupial pouch" is not formed. In younger individuals 

 these lamellae are very small, hardly distinguishable. The smallest in 

 which I found traces of them was 64 mm. long (Station No. 2980). 

 In all smaller specimens there was no trace of them, and I was unable 

 to make out whether the} 7 were young males or } T oung females, as the 

 male tubercle is generally not visible; in one individual only (55 mm., 

 Station No. 2980) I thought I could see this tubercle. Upward of the 

 size of about 65 mm. it is possible to tell the males from the females, 

 and it is remarkable that in the material examined females were 

 more abundant, there being only 9 males, as against 23 females. It 

 is remarkable, further, that the largest male was oniy 76 mm. Ion •, 

 and that all specimens above this size were females (IT of them). 

 Sars's largest specimen of 98 mm. is said to be a male, while Wood- 

 Mason's specimen (91 mm.) was a female. 



The fact that even the largest females did not have the marsupial 

 pouch completei}^ developed indicates that they were not fully mature 

 sexuall\ T . This makes it probable that they would have to develop 

 further before being able to propagate, and suggests the possibilit} T 

 that they may attain the size of G. ingens, in which case they might 

 assume the characters of the latter, thus making G. ingens the full- 

 grown female of this species. 



Most of the specimens were from the Eastern Pacific (California 

 region), ow\y one j^oung one (55 mm., Station No. 2384) being from the 

 Gulf of Mexico. This is distinguished by a very long rostrum and 

 very long póstero- inferior spines. The rqstruni, in front of the supra- 

 ocular spines, is slightly longer than the rest of the carapace (exclud- 

 ing the postero-dorsal spine), and was even longer than that, since the 



«ISars, p. 27, and Plate III, figs. 14 and 15. 



