106 THE VOYAGE OF H.M.S. CHALLENGER. 



median dorsal spine, crosses the middle line above the posterior edge of the first 

 abdominal somite. The eyes are nearly cylindrical, with very short stalks, and the 

 hind body is flat and wide. 



The youngest larva (No. 1, shown in PI. XII. fig. 4) is so similar to the one repre- 

 sented in Claus's figure 22 B, that wo must believe that they are closely related. The 

 Challenger larva from St. Vincent is 4 '16 mm. long, and our measurements indicate 

 that, if there be a younger stage, its length should be 3 '33 mm., while Claus's larva, 

 from Messina, is about 3 mm. long, and it is highly probable that it belongs to 

 this species, and is therefore a Coronis, although this author held that it is either 

 a Pseudosquilla or an AUma} The spines of the carapace are longer, and the eyes 

 lono'er and narrower in our species than in Claus's figure, but these are the greatest 

 differences, 



In our larva No. 1 (PI. XII. fig. 4) the first antennae have only two branches, the 

 second antennae have no flagellum, and the third, fourth, fifth, sixth, seventh, and eighth 

 thoracic somites have no traces of appendages, and they are equal in length, although 

 the eighth is wider than the others. The thoracic ganglia are marked off by fissures 

 but they are in contact with each other. 



There are five distinct abdominal somites with separate ganglia and functional 

 appendages, each with an appendix interna or retinaculum on the thoracic edge of its 

 endopodite (PI. XII. fig. 4). 



The sixth abdominal somite is obscurely indicated, and its appendage is represented 

 hj a bud (PI. XIII. fig. 1). The carapace has a small dorsal median spine on its 

 posterior edge, the rostrum is about half as long as the carapace, with three small spines 

 on its ventral surface, and about as long as the divergent posterolateral spines. The 

 lateral edges of the oval carapace are fringed with numerous minute serrations, but 

 there is no large tooth on the ventral side of the base of the postero-lateral spine. The 

 raptorial claws, even at this early stage, are flat and wide, and the carpus has a single 

 prominent tooth close to its base, on its anterior edge. 



A profile view of the next stage (No. 2) is given in fig. 11 of PL XIII. A 

 small bud now represents the flagellum of the second antenna (PI. XIII. fig. 4), and the 

 appendages of the third, fourth, and fifth thoracic somites are also represented by buds 

 (PL XIII. fig. 5), and the ganglia of the sixth, seventh, and eighth thoracic somites have 

 separated from each other. The sixth abdominal ganglion and somite are now distinct, 

 and the rudimentary appendage (PL XIII. fig. 3) consists of a long acute simple spine 

 and two rounded lobes. The posterior edge of the telson, which was transverse in 

 stage 1 is now angulated on the middle line. The next stage is shown from below 

 in PL XIII. fig. 6. All the appendages and somites are now represented, the lateral 



1 Metamorphose der Squilliden, p. 144. 



