34 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxi. 



tio-. '1(\ iind sliows a nitlicr more advanced stage, although it comes 

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

 plate of larger specinuMis. Sars's tigure is about intermediate between 

 my figures 'Ih and 2c, representing specimens of 55 and &% mm., 

 lespectivel}'. 



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

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

 females are readily recognized by the presence of mai'supial lamella 

 at the bases of the thoracic legs. These lamelhii "are absent in the 

 male, l)ut 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 voung and not quite adult females, however, the marsupial 

 lamelhe are comparative!}^ small. In all the females of the present 

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

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

 that a '•maisui)ial pouch" is not formed. In younger individuals 

 these lamelhe are very small, hardh^ 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 1 was unable 

 to make out whether they were 3'oung males or _young females, as the 

 male tubercle is generally not visible; in one indi\'idual only (55 mm., 

 Station No. 2980) I thought 1 could see this tubercle. Upward of the 

 size of about ()5 nuu. it is possible to tell the males from the females, 

 and it is remarkal)le 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 only 76 nun. lou'j-, 

 and that all specimens above this size were females (17 of them). 

 Sars's largest s[)ecimen 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 completely developed indicates that they were not fully mature 

 sexually. This makes it prol)able that they would have to develop 

 further before being able to propagate, and suggests the possibility 

 that they may attain the size of G. inycns^ 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), onl}' one young one (55 mm., Station No. 238-1:) being from the 

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

 very long postero- inferior spines. The rostrum, in front of the supra- 

 ocular spines, IS slightl}' longer than the restof the carapace (exclud- 

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



«!Sars, p. 27, and Plate 111, figs. 14 and 15. 



