ENTOMOIDA. ENTOZOA. 407 



ORDER I ELMINTHOGAMA. Vers Camtaires, Cuv. 



Worms generally living on the exterior of aquatic animals, or 

 in the interior parts of others, with a mouth and anus, and 

 the sexual organs separate ; two nervous filaments in some 

 arising near the opening of the oesophagus. 



FAMILY I. ENTOMOIDA. Epizoaires, Lam. 



Worms living on the exterior parts of aquatic animals, with ap- 

 pendages resembling feet or organs for locomotion, and the 

 body in the females terminated posteriorly by two ovaries. 



This family, comprehending the genus Lerncea of Linnaeus, consists of parasitical 

 worms attached to the head and other parts of fishes. From their external situation 

 they possess not only organs for piercing and sucking animal substances, but also parts 

 variously constructed for attaching themselves to the surface of bodies ; and their 

 body is necessarily of a firmer consistence than those worms which are entirely con- 

 cealed in the substance of other animals. The general structure and habits of the 

 family are still but imperfectly known. A new species, named Lerncea elongata 

 by Professor Grant, is minutely described by that gentleman in the Edinburgh 

 Journal of Science, vii. 147 ; and the anatomical details there given may be con- 

 sidered as applicable generally to the structure of other individuals of the genus. 



TRIBE I. THORACICA. 



Body divided into two parts, the one representing the head and 

 thorax united, the other the abdomen. 



Gen. LEHNANTROPUS, LERNEOPODA. Blainv. ; which compose the genus 

 Chondracanthus of Cuvier. 



TRIBE II. CAPITATA. 

 Anterior extremity of the body seeming to have a distinct head. 



Gen. LERNACANTHUS, LERNENTOMA, (Entomoda, Lam.) 



TRIBE III. ANGUILLIFORMIA. 



Body long, linear, with appendages in the form of fins at the pos- 

 terior extremity ; anterior extremity with some small tenta- 

 cula. 

 Gen. LERNEOPENNA, Blainv. 



TRIBE IV. RHIZODA. 



Body slender and elongated, with appendages only at the ante- 

 rior extremity. 



Gen. LERNEOCERUS, LERNEOMISUS, LERNCEA. 



TRIBE V. ACOLA. 

 No exterior appendages, the ovaries at most projecting. 



I. Ovaries exterior, at the posterior extremity of the body. 



Gen. FOROCULUM. 



II. Ovaries not projecting. 



Gen. NEMERTES, PLANARI^E. 



