REPORT ON THE STOIVIATOPODA. 113 



The adult genus Pseudosquilla is not sharply limited, as the various species are very 

 closely related to Gonodactylus on the one hand, and to Coronida and Coronis on the 

 other, and we should not expect the larval type to be more definite than the adult, and 

 as a. matter of fact the collection contains larvse which closely resemble Pseuderichthus 

 although they may possibly be Gonodactylus larvae, and others which may possibly be 

 Lysiosquilla larvae. 



The Challenger collection contains very few young larvae of this type, and I have 

 not been able to trace its metamorphosis, although Claus has given reasons for 

 believing that it hatches as an Evichthoidina, and afterwards undergoes a retrograde 

 metamorphosis, loosing and afterwards redeveloping all the thoracic appendages, except 

 the first and second pairs. 



The Erichthoidina from St. Vincent, shown in PL XII. fig. 3, may possibly be a 

 young Pseudosquilla, although it more closely resembles the Gonodactylus Erichthus. 



The Gonerichthus larva and the Metamorphosis of Gonodactylus. 



The last larval type which I shall discuss is represented in the Challenger collection 

 by numerous specimens, a few of which I have selected and drawm. 



One of these, from St. Vincent, is shown in PL XIL fig. 5, while the telson and 

 uropods of another specimen, from the Celebes Sea, in the same stage of development, 

 and belonging to the same or a closely related species, are shown in PL XIIL fig. 9. 

 The fully grown larva, Ix^j^ inches long, of another species from the West Pacific, 

 lat. 17° 29' N., long. 141° 21' E., is shown in profile in PL XV. fig. 11, and from above 

 in fig. 6, and the telson and ui'opods of a closely related species 1^ inches long, from 

 Volcano Island, in the West Pacific, are shown, more enlarged, in fig. 7. • 



The carapace of another species, ^^^j inch long, from the Celebes Sea, is showai in 

 PL XV. fig. I, and the telson of a young Gonodactylus of the Chircujra type in the adult 

 condition is shown in PL XVL fig. 5. This specimen, which is y\j- inches long, was taken 

 with the trawl in IS fathoms, west of the Philippine Islands, at Station 208. This latter 

 specimen had the raptorial claw fully developed, and it exhibited all the characteristics of 

 the adult Gonodactylus. It is certainly a young Gonodactylus closely related to, or 

 possibly a specimen of, Gonodactylus chiragra, and a comparison of its telson and uropods 

 with those of the various larvae which have just been noticed will show that there is the 

 closest agreement in every particular. In all of these larvae, as in the young Gono- 

 dactylus, the sixth abdominal somite has a pair of submedian spines near its posterior 

 edge, and its postero-lateral angles are produced into acute spines. The telson is slightly 

 wider than long, its submedian spines are long and slender, but shorter than they are in 

 Pseuderichthus, and without the movable spinules of the latter. The telson is notched 

 on the middle line, and there are from fourteen to twenty small secondary spinules on 



(ZOOL. CHALL. EXP. — PART XLV. — 1886.) Yy 15 



