624 CLASS x. 



I think it is only a monstrous variety of Limulus moluccanus. Several 

 fossil species are known from the lithographic formation ; see my monograph, 

 Tab. 7. 



ORDER II. Ichthyophthira. 



Mouth suctorial. Rostrum tubular, including two mandibles 

 setaceous, acuminate, formed of labium and labrum conjoined, 

 sometimes concealed, or a tubercle instead of haustellum. Anterior 

 feet supplied with hooks or acetabula for fixing the body. Animal- 

 cules, in the adult state, adhering parasitically to fishes, often 

 deformed, soft, with segments obsolete. Females supplied with 

 oviferous appendages (external ovaries). 



Fish-lice. We prefer this name to that of Parasita, introduced 

 by WIEGMANN, because in the class of insects an order of Parasitica 

 had been previously adopted. The animals when young swim 

 freely about, by means of feet with long hairs, and resemble the 

 young animals of Cyclops. 



Comp. on this order BLAINVILLE MSmoire sur les Lern4.es, Journal de 

 Physique, de Chim., d'Hist. nat. &c. Tom. 95, Paris, 1822, pp. 372 380, 

 and pp. 437 447, and by the same the Article Lernee in Dictionnaire des 

 Sciences nat. xxvi. 1823, pp. 112 130. A. VON NOKDMANN Mikrogra- 

 phische Beitrage, 2tes Heft. Berlin, 1832, 4to. H. BUKMEISTEK Beschrd- 

 bung einiger Schmarotzerkrebse. Nov. Act. Acad. Cces. Leap. xvn. 1835, pp. 

 269 336; H. KROEYER Om Snyltekrebsene, Naturh. Tidsskr. i. 1837, pp. 

 172 and foil., pp. 25-2 and foil., pp. 470 and foil., pp. 605 628, II. 1838, 

 pp. 852, pp. 131157- 



Family II. Lernceacea (Penellina BURM.) Body in adults not 

 articulate, cylindrical or sacciform. Articulate feet none. 



Lerncea L. (Lernceocera BLAINV., V. NoRDM.). Body ventri- 

 cose, mostly incurved. Three or four appendages, branched at the 

 apex or bifid, around the head, for fixing the body. 



Sp. Lerncea Iranchialis L., Encyl. meth., Vers. PL 78, fig. 2, GURIN Iconogr., 

 Zooph. PL 9, fig. i ; with three branched little horns on the head ; the 

 ovisacs are two long tortuous strings ; this species fixes itself to the gills of 

 the cod-fish; comp. C. N. (OZEMAN) Vitgezogte Verhandelingin, II. 175 7, 

 bl. -282 and foil., PL 14, ill. bl. 232 and foil., PL 23. 



There was much doubt formerly respecting the place of these gill-worms 

 in the natural arrangement of the animal kingdom. CUVIEE placed them 

 amongst the intestinal worms (intestinaux cavitaires, see R. Ani. ie e*dit. 

 ill. p. 255), as a distinct and anomalous family. The resemblance to some 

 other parasites, which had been referred to the Crustacea, caused indeed a 



