MARINE CRUSTACEANS. 



443 



Geuus Pyrgoma Leach, 1817. 



12. Pyrgoma cancellatum Leach, 1824. Darwin, ii. p. 362. 



Darwin did not know from what locality his specimens of this species had been brought. 



but supposed it to be the West Indies 

 Atoll in 26 fathoms. 



The present specimens were dredged in Suvadiva 



13. Pyrgoma grande (Sowerby), 1839. Darwin, ii. p. 365. 



This species lives inside the polyps of Euphyllia. The outside of the basal cup of the 

 cirripede often shows septa formed by the polyp, so that it would appear that the soft 

 parts of the polyp adapt themselves to the invasion by growing over the foreign body. [The 

 same or another species lives commonly in the Maldives on Galaxea. Ed.] 



Danvin reports P. grande from "two sorts of corals," and it is evident from his figure 

 that in at least one of these the same relation between the barnacle and the coral is found 

 as in our specimens. 



14. Pyrgoma madreporae n. sp. (Fig. 119). 



Diagnosis : " A Pyrgoma with the shell flat, oval, the opening keyhole-shaped ; the 

 ridges well developed, alternately long 

 and short, rather wide apart, about 

 11 in a quadrant, projecting somewhat 

 at their outer ends ; basal cup very 

 strongly ribbed inside ; scutum of 

 simple, triangular shape, with a 

 rounded basal edge and a well-de- 

 veloped adductor ridge ; tergum also 

 triangular, with a short spur; cirri 

 delicate, the series growing longer from 

 before backwards; mandible with 5 

 teeth, exclusive of the lower angle, 

 which bears a number of bristles, the 

 teeth growing smaller from above 

 downwards." 



Fig. 119. Pyrgoma madreporae; whole animal imbedded in coral, with 

 detached scutum and tergum seen from the inside. 



Breadth of largest specimen : 8 mm. Colour in spirit, white. 

 Found in a Madrepora at Hulule, Male Atoll. 



Genus Chelonobia Leach, 1817. 



15. Chelonobia testudinaria (Linn.), 1758. Darwin, ii. p. 392. 



Two specimens were taken on the carapace of the turtle Chelone midas in Minikoi. 



16. Chelonobia caretta (Spengler), 1790. Darwin, ii. p. 394. 



Several specimens were found in the skin on the legs of the turtle Chelone imbricata 



in Minikoi. 



G. 



57 



