480 Bibliographical Notice. 



appendice se'tace et grele " of the hook-shaped antennae is for Dr. 

 Kroyer the first pair of antennae, removed further back ; and the 

 hook-shaped organs described by Milne-Edwards as the sole pair of 

 antennae Dr. Kroyer consequently describes as a second pair. These 

 organs correspond in shape and place entirely with those organs in 

 Caligus which in Milne-Edwards' s description are counted as the first 

 pair of footjaws ; and Dr. Kroyer therefore, in opposition to Milne- 

 Edwards, describes them as a second pair of antennae also in Caligus. 

 "What Milne-Edwards describes in Argu lus as " une seconde paire 

 d' appendices antenniformes" represent, according to Dr. Kroyer, the 

 first pair of ordinary feet, occupying a place somewhat more advanced 

 and removed to the sides away from the mouth than in Caligus. The 

 correctness of this view is confirmed by the circumstance that the 

 sucking-cups which immediately follow them, evidently, as the de- 

 velopment of young Argulus and the analogy of Gyropeltis show, 

 correspond to the second pair of feet in Caligus. The author con- 

 siders the fork-shaped organ observed in Caligus behind this thick 

 second pair as a deformed pair of feet, so much the more as it is 

 supported by a separate and independent joint of the body. Both 

 Argulus and Caligus will thus appear to have seven pairs of feet, ex- 

 biting a strict parallelism. The so-called tail in Argulus corre- 

 sponds, according to Dr. Kroyer, merely to the so-called genital 

 joint in Caligus, containing as it does the organs of generation : the 

 real tail is quite rudimentary in Argulus, but is nevertheless repre- 

 sented — namely, by the appendages described by Milne-Edwards 

 as " une paire d' appendices de forme oval aire " (p. 443). In con- 

 clusion, the author adduces the circumstance that the sting placed 

 in front of the beak in Argulina has nothing to do with the organs of 

 the mouth, but is rather to be compared to the poisonous sting of 

 Cyclopsine Castor, Szc. ; that several Siphonostoma, such as Noto- 

 delphys and Doropygus, resemble Argulus in being without external 

 oviducts ; and that the single eyes placed in a triangle are met with 

 both in free Copepodes (Sap>phirina) and in larvae of the parasites, 

 from all of which he concludes that there is no reason for making a 

 new order of Argulini, or separating them from Siphonostoma. He 

 describes three new species of Argulus from America, raising the 

 number of species in the group of Argulini to thirteen, of which 

 eleven are American — from which it should seem as if it belonged 

 principally to the New World. 



There are, upon the whole, a great many American species 

 amongst those which are described in this paper ; and in mentioning 

 three new species of Chondr acanthus from Valparaiso, the author 

 alludes to a parallelism, observed by him before, between the fauna 

 of North Europe and of the littorale of Chili. Dr. Kroyer abandons 

 as untenable, on account of intermediate forms (of which he describes 

 some, particularly Alebion Carcharice, Kr.), the distinction between 

 Caligini and Pandarini. He preserves the genera Lepeophtheirus, 

 Nordm., and Scicenophilus, Van Ben., which Steenstrup (I. c.) has 

 proposed to suppress ; but prefers to reunite Calistes, Don., and 

 Dysgamus, Steens., with Trebius, Kr. (Synestius, Steens.), and Parape- 



