1312 



CRUSTACEA. 



Fam. III. NICOTHOIDJE. 



Ergasilidis affinis. Antennae posticae perbreves vel rudimentariae. 

 [Corpus lobis tumidis prodigiosis lateraliter productum.] 



G. Nicothoe ; And. et Edw. 



The genus Bomolocus, Nordniann, is of doubtful place. The general 

 form is like that of Ergasilus, but only two antennae are mentioned, 

 and these are peculiar in having a spinous basal portion for attach- 

 ment and a pauci-articulate flagellum. 



The homologies of the Ergasiloidea will be inferred at once from a 

 comparison of the animals with the series of parts in the Cyclopoidea 

 (Cyclops or Corycaeus).* The four pairs of natatories are in both 

 groups appendages to the eighth, ninth, tenth, and eleventh normal seg- 

 ments. In Nicothoe, the three pairs of appendages preceding, are 

 homologues of the maxillae, maxillipeds, and first pair of legs (fifth, 

 sixth, and seventh normal segments) ; while the buccal trunk includes 

 or corresponds to the mandibles and lips (fourth normal segment). 

 In Ergasilus, there are two pairs of antennae, as in Corycaeus, which 

 completes the animal anteriorly, these corresponding to the second 

 and third normal rings of other Crustacea. The second pair of an- 

 tennae are considered maxillipeds by Milne Edwards. 



Van Beneden, in a recent paper on Nicothoe,f in which the embry- 

 ology is quite fully illustrated, observes, that the species appears from 

 its course of development to belong to a different type from Ergasilus. 

 This genus and Caligus he refers to the same type with Cyclops, and 

 considers Nicothoe as pertaining to another category. 



* The appendagas in Corycaeus and the allied genus Sapphirina are given in order on 

 Plate 92, figures 1 a, b, c, etc., pertaining to Sapphirina, and 1 a', V, etc., to Corycxus. 

 f Mem. Acad. Roy., Belg., vol. xxiv. 



