REPORT ON THE STOMATOPODA. 99 



The Lysioerichthus larva, and the Metamorphosis of Lysiosqidlla. 



If my decision tliat all the Alima larvae are young Squills be correct, we must look 

 for the larvae of all the other genera of Stomatopoda among the Erichthi and 

 SquilJerichthi ; or, as SquiUerichthns is simply an advanced Erichthus, among the 

 Erichthi. 



The series of Erichthu.'i larvae is so complete, and transitional forms are so 

 numerous, that it is veiy difficult to divide the group into minor groups ; and while it is 

 obvious that there are several distinct larval types, they are so intimately imited by 

 intermediate forms that the attempt to study them is ver}^ puzzling. The genera 

 merge into each other in such a way that it is difficult to find any strictly diagnostic 

 characteristics, but this is no more than we should expect from the absence of sharply 

 limited genera among the adult Stomatopoda. 



I have shown that the species of LysiosquiUa, in which genus I include Coronis, 

 and the species of Squilla including Chlovidella, exhibit proofs of divergent descent 

 from a common stem form, which was more like Coronis and Chloridella than it was 

 like the more divergent LysiosquiUa and Squillie ; and as I have also shown that the 

 larvae of all the species in the Squilla-hvAnQh. from this common stem are Alimse, we 

 naturally turn to the Alima-Vik& Erichthi in our search for the larval t}^3e of the second 

 or Lysiosquilla-hranch.. 



In addition to their features of relationship to the adult genus Squilla, the Alima 

 larvae agree with each other in the general occurrence of marginal spines on the lateral 

 edges of the carapace, the length of the telson, which is almost always greater than its 

 breadth, the flatness of the hind body and the presence of marginal spines on the inner 

 edge of the dactylus of the raptorial claw. Squilla and LysiosquiUa agree with each 

 other in the flatness of the hiud body, and in the presence of spines on the dactylus, but 

 the Alima Ihlyvs. shows its relationship to Squilla by the presence of numerous 

 secondary spines between the submedian and intermediate marginal spines of the telson, 

 by the small number of spines on its dactylus, and by the fact that the inner spine of 

 the uropod is always longer than the outer. 



Now there is a group of Erichthus lawsa, of which Erichthus duvaucellei {LysiosquiUa 

 maculata ?) (PI. X. fig. 7), and Erichthus nmltispinosus {LysiosquiUa excavatnx) (PI. XL 

 figs. 1, 2 and 3) are examples, which show by the flatness of the hind body, and by the 

 presence under the cuticle of the dactylus, in the older larvae, of traces of marginal spines, 

 that they are either Squilla or Lysiosqtiilla larvae. Claus refers them to the genus 

 Squilla, but as the marginal spines are usually more numerous than they are in any 

 known Squilla or in the Alima larva, we must exclude the genus Squilla in our attempt 

 to trace them to their adult form. In some of these larvae there are as many as seventeen 

 of these rudimentary spines on the dactylus, and they are seldom less than six, and there 



