i] 
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PACIFIC COAST OLIGOCH MTA. 1 
DETAILED DESCRIPTION OF NEW SPECIES. 
Benhamia nana pn. sp. 
Figs. 1-42. 
Habitat. San Blas, 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 380 mm. 
Somites 110. 
Clitellum comprises somites xiil to xx, being complete in the central somites, 
but incomplete in xiii, xvii, xviii and xix. 
First dorsal pore ii-iv. 
Spermathecal pores, one pair vii-vill, and one pair between viii-ix, rather close 
together in a ventral grove. 
Oviducal pores open separately in xiy in front of sets 1 and 2. 
Prostate pores, one pair in xvii, one pair in xix, open with penial sete. 
Penial sete, two in each pocket, the largest of which is furnished with 12 or 
more bristles. 
Common sete, 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. 
Caleiferous glands two pairs, one in xiv, one in xy. 
Septal 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, X1. 
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. 
Spermathece in vii-vili, yili-ix. The apical part much smaller than the 
basal part, the latter with a small diverticulum placed high up near the constriction. 
Nephridia arranged in three rows on either side of the median line. Pair a 
open in front of the outer couple of sete, pair b and ¢ open laterally and dorsally as 
regards the sete. The posterior nephridia furnished with a large celomie cellular 
mantle. The nephridia in each somite of about equal size. The nephridia on each 
side about equidistant, but the dorsal nephridia ¢ are much further apart from the 
median line than from nephridia 0. 
