BY N. A. COBB. 771 



•1 6-7 12'5 M 96-2 



■5 13 1-8 2-5 r ^"^ '"™- The tail is somewhat irregularly conoid to 

 near the middle ; thence to the slightly swollen terminus it is 

 uniformly as wide as the spicula. These latter are nearly half as 

 long as the tail, and are arcuate, particularly in the distal part. 

 They diminish uniformly in size from the scai'cely contrasted 

 proximse to the acute distal extremities, and are said to be 

 destitute of accessory pieces. The supplementary ventral organ 

 is one-fourth as long as the spicula and is situated in fi'ont of the 

 anus at a distance from it equal to the length of the tail. 



Habitat. — Roots of coralline, coast of England. 



•3. A. acuminata, Eberth. The following formulae and descrip- 

 tions are made up from the notes of Bastian, Biitschli and De Man, 

 with the aid of my Naples material. Bastian observed neither 

 the pectoral hairs of his linialis, nor the porus of his pellucida, 

 and thus made out two species from specimens belonging in reality 

 to but one, — the one already described by Eberth under the 

 name Odontobius acuminatus. De Man's tyrrhenica is no doubt a 

 small acuminata. 



■6 2- ^2-8 %'d. T? 2-3 mm. This is a slightly heterocephalous species, 

 with a small pharynx ending nearly opposite the cephalic setfe. 

 The neck is nearly conoid. The head is rounded in front, and is 

 set off by an almost imperceptible constriction just behind the 

 cephalic setaj. Three lips, without papillte, are barely distinguish- 

 able. A longitudinal row of five closely approximated pectoral 

 hairs is found on either lateral line at a distance from the 

 mouth one-sixth as great as that of the nerve-ring from the 

 mouth. The lateral organs are situated half way between 

 the cephalic setae and the porus. The conoid resophagus is 

 one-half to two-thirds as wide as the neck, and a distinct 

 cardiac collum marks its junction with the intestine. The 

 thin wall of the tessellated intestine is composed of a single 

 layer of cells of such a size that seventeen side by side make up 

 the circumference. The unicellular ventral gland is situated 

 just in front of the cardiac collum and is not reflexed as in 

 Anticoma typica. It empties by means of a rather wide duct 



