116 AMERICAN MARINE CONCHOLOGY. 



Genus TERGIPES, Cuvier. 

 Ann. du Mas., xix. 1813. 



1. T. DESPECTA, Johnston. Fig. 240. 



(Eolis.) Mag. Nat. Hist., viii. 378, f. 35«. 



Animal colorless, with a zigzag olive stripe along the back ; 



branchife large, ovate, in a single series along each side ; dorsal 



tentacles long; angles of foot not produced. 



Length 6, breadth 1.25 mill. 



Massachusetts; Scotland. 



2. T. GYMNOTA, Couthony. Fig. 241. 



(Eolis.) Bost. Journ. Nat. Hist., ii. 69, t. 1, f. 3. 1838. 



Animal small, tapering to a fine point, watery white; tentacles 

 short, the posterior pair minutel}' serrated ; branchia? in seven 

 lateral clusters of about five each, slightly club-shaped, having a 

 reddish-brown centre. 



Length 25, diam. 2.5 mill. 



MastacJmsetis. 



Genus CALLI0P.S;A, Orb. 

 Mag. ZooL, t. 108. 1837. 



1. C. FUSCATA, Gould. Fig. 241a. 



Invert. Mass., edit. ii. 250, t. 16, f. 218-221. 1870. 

 Animal semicylindrical, attenuated behind, dark slate-colored ; 

 head not distinct, excavated in front ; tentacles two, long, pointed; 

 branchife long, club-shaped, slender at base, allernating in two 

 parallel rows on the two j^osterior tliirds of each side, the lower 

 series much the smaller; foot bilobed in front, contracted poste- 

 riorly. 



Length 7.5, diam. .8 mill. 



MassacJiii setts. 



Family HERM^ID.^. 



Synopsis of Genera. 

 Tentacles two, longitudinally folded ; head without lobes ; gills elongate, 

 papillose, smooth, arranged along the sides of the back. 



Herm^a, Loven. 

 Head without tentacles, produced into a lobe on each side ; gills papillose, 

 arranged in transverse rows on the sides of the back. 



Alderia, Allman. 

 Tentacles two, simple, undefended, contractile, sublateral ; a large labial 

 veil, produced on each side into an oblong, flat lobe ; gills simple, papil- 

 lose, lateral, in a simple series on each side of the back ; foot rather 

 broad. Clcelia, Loven. 



