140 ANNELIDES. APODES. 



antenna subulate, small, the middle ones obsolete, the exterior 

 largest ; two distinct eyes ; scales on the back. 



The body in this genus is oval or elliptical, terminated anteriorly by a compres- 

 sed, convex, and projecting head. The branchiae, scarcely perceptible, cease to al- 

 ternate after the twenty-fifth pair of setiferous papillae. 



* Dorsal scales covered by felted bristles. 



H. aculeata, Lam. (Apkrodita, Lin.) Body oblong, hairy, spinous, 

 and shining ; dorsal scales with fuscous dots ; Inhabits European 

 seas. B. Penn. Brit. Zool. iv. pi. 25, fig. 1. 



This species is very common, and is popularly called the Sea Mouse. The sides 

 are ornamented with changeable green hairs of a brilliant appearance, mixed with 

 sharp spines. The mouth is placed beneath, and the belly is naked. Each pedi- 

 form appendage is furnished with 6ve or six strong spines, and there are about thir- 

 ty-six on each side. It grows to the length of four or five inches. 



** Dorsal scales uncovered. 



H. hystrix, Lam. Body oblong, depressed, fuscous, yellow ; dorsal 

 scales naked, pale ferruginous. Seas of Europe Lam. v. 307 



Gen. 17. PALMYRA, Lam. 



No tentacula at the orifice of the proboscis ; jaws semicartila- 

 ginous ; exterior antennae larger than the three others ; two 

 eyes ; no dorsal scales. 



P. aurifera, Sav. Body shining with a golden lustre ; bristles 

 widening and obtuse at the summit, and very brilliant ; body ob- 

 tuse at both ends, and of thirty segments ; no branchiae nor su- 

 perior cirri to the twenty-eighth pair of pediform papillae. Inha- 

 bits Indian seas Lam. v. 306. 



ORDER III. APODES. 



Destitute of feet ; that is, without setiferous and retractile pa- 

 pillae ; branchiae, when known, disposed interiorly along the 

 body ; no antenniferous head. 



The animals of this order, though possessing a true circulation and red blood, seem 

 the most imperfect of the class. They are destitute of head, tentacula, antennae, and 

 pediform papillae; and their branchiae are interior, in or under the skin, and so 

 small in certain races as to be with difficulty recognized. They are generally naked, 

 or furnished with bristles which are not retractile. The greater number live in 

 the water ; the others in mud or humid earth. The order is divided by Lamarck 

 into two families, Echiurece and Hirudinece. 



FAMILY I. ECHIURE^. 

 Body with the bristles projecting, but not retractile. 



Gen. 1. CIRRATULUS, Lam. 



Body elongated, cylindrical, annulated, furnished on the sides 

 of the back with a row of very long setaceous cirri, almost 

 dorsal, and two rows of short spines placed below ; two fasciculi 

 of long projecting cirri inserted below the anterior segment ; 



