REPORT ON THE STOftlATOPODA. 83 



ventral surface of the basal joint of the uropod is usually much longer than the outer, 

 and is usually furnished with a tooth on its outer edge, and in the older specimens there 

 are indications, underneath the cuticle, of spines on the inner edge of the dactylus of the 

 raptorial claw. In his classical paper on the Metamorphosis of the Stomatopoda, Claus 

 pointed out that there are so many features of resemblance between the Alima and the 

 various forms oi Erichthus that the larval nature of Alima cannot be doubted. Milne- 

 Edwards and Dana had found it difficult to cbaw any line between the two genera ; the 

 first-named writer placing in the genus all Erichthidae in which the ocular segment is 

 exposed, while Dana includes in it those forms in which the distance from the anterior edge 

 of the carapace to the mouth is greater than the distance from the mouth to the posterior 

 edge. Claus shows that neither of these features serves to discriminate between 

 Alima and Erichthus in every case, and he figures and describes a larval type which is 

 intermediate between the two, having the elongated flattened carapace and the exposed 

 eyes, but the mouth well forward, and the thoracic region well covered by the carapace. 

 For this intermediate larval type he proposes the name Alimerichthics. Claus was not 

 able to connect any one of his Alinue with a specific' adult, but he shows that they 

 resemble the adults of the Sqiiilla type very closely, and he correctly decides that 

 they are the larvae of this type, although he erroneously believes that they belong to 

 the Lysiosquilla branch, rather than to the true Squillie} He says there can be no 

 doubt that we must seek their adult representatives in the Squilla-grou-p, and that the 

 Alima lai-va, as distinguished from Erichthus, belongs exclusively to the genus 

 Lysiosquilla, which is characterised, like the Alima larva, by the elongation and loose 

 articulation of the abdomen. The lower members of the genus Squilla are loosely 

 articulated, like the Lysiosquilla, and the hind body is about as long in the one genus 

 as it is in the other, and there is therefore no reason for believing that any of these 

 larvae are young Lysiosquillse, although later researches have shown that he is correct in 

 his surmise that they pertain to the Squilla-gvon^. 



In a paper which was published in 1879-1 described a series of Alima \axvsd, which 

 were procured in abundance in the Chesapeake Bay, a locality where Squilla empusa is 

 common, while no other Stomatopod is known to occur there, and I therefore advanced 

 the opinion that this larva, a young stage of which is shown in figs. 4 and 5 of 

 PI. L, is a young Squilla. Three years before, Faxon reared from a similar but slightly 

 more advanced larva, a young Squilla, which had the characteristics of the adult Sqtdlla 

 empusa, and although his results were not published until 1882Hhe proof that Alima 

 is a young Squilla is due to him. It is of course possible that some species 

 of Lysiosquilla may also pass through an Alima stage, but I shall show that, among 



' Metamorphose der Siiiiilliaen, p. 154. 2 On the larval stages of Squilla empusa. 



5 Selections from Embryological Monographs compiled by Alexander Agassiz, Waller Faxon, and E. L. Mark, 

 I. Crustacea, Cambridge, 1882, Bull. Mm. Con\p. Zool., vol. ix. No. I., pi. viii. figs. 2, 3. 



