PACIFIC COAST OLIGOCH^TA. 127 



DETAILED DESCRIPTION OF NEW SPECIES. 



Benhamia nana n. sp. 

 Figs. 1-42. 



Habitat. San Bias, territory of Tepic, Mexico. I found a small number of 

 specimens, of which only two possessed a perfectly developed clitellum, October, 1894. 

 A real tropical form. 



Color. Deep reddish-brown and very opaque. 



EXTERIOR CHARACTERS. 



Size small, 20 to 30 mm. 



Soniites 110. 



Clitellum comprises somites xiii to xx, being complete in the central somites, 

 but incomplete in xiii, xvii, xviii and xix. 



First dorsal pore iii-iv. 



8permathecal pores, one pair vii-viii, and one pair between viii-ix, rather close 

 together in a ventral grove. 



Oviducnl pores open separately in xiv in front of set* 1 and 2. 



Prostate ports, one pair in xvii, one pair in xix, open with penial setag. 



Penial setm, two in each pocket, the largest of which is furnished with 12 or 

 more bristles. 



Common setce, distance between the dorsal couples equal to that of the ventral 

 couples. 



INTERNAL CHARACTERS. 



Buccal cavity with a dorsal pocket. 



Suprapharyngeal glands with pharynx opening far forwards. 



Gizzards in viii and ix. 



Calciferous glands two pairs, one in xiv, one in xv. 



Sejytal glands very minute in ix, x, xi. 



Sacculated intestine commences in xiv. 



Typhlosole very strongly developed in xviii to xxii. 



Sperm-sacs two pairs in x, xi. 



Ciliated rosettes in x, xi. The lower part of the spermducts in xvi, xvii, xviii 

 is thickened and twice the diameter of the anterior part. 



Prostates are straight and tubular, each one confined to one or two somites. 



Spermathecce in vii-viii, viii-ix. The apical part much smaller than the 

 basal part, the latter with a small diverticulum placed high up near the constriction. 



Nepthridia arranged in three rows on either side of the median line. Pair a 

 open in front of the outer couple of set*, pair h and c open laterally and dorsally as 

 regards the setfe. The posterior nephridia furnished with a large cffilomic cellular 

 mantle. The nephridia in each somite of about equal size. The nephridia on each 

 side about equidistant, but the dorsal nephridia c are much further apart from the 

 median line than from nephridia h. 



