ANNELID GENUS CAMBARINCOLA — HOFFMAN 285 



Testes. The spermatogenic tissue of branchiobdellids is con- 

 centrated into one or two pairs of testes located on the posterior face 

 of segmental septa 4/5 and 5/6, or only on 5/6. As a rule the testes are 

 perceptible as such only in immature animals, sexually mature adults 

 show the condition in which the gonads have liberated morulae into the 

 coelom, the fluid of which becomes filled with masses of spermatozoa 

 and disintegrating blastophore material. As a rule, however, the 

 sperm masses are easy to observe in most whole mounts, particularlj^ 

 as they tend to become oriented in clusters before the openings of the 

 funnels, and provide evidence concerning the distribution of the testes. 

 At least one genus {Branchiohdella) is provided with testes only in 

 segment vi, a condition upon which Goodnight (1940b) has founded a 

 subfamily Branchiobdellinae. That this difference is a fundamental 

 one has been established by the recent examination of a European 

 species of the genus, which has revealed additional peculiarities of the 

 reproductive system as well. All the North American genera which 

 have been studied in detail have two pairs of testes, and thus belong to 

 Goodnight's subfamily Cambariucolinae. With Branchiohdella still 

 very poorly known taxonomically, it is premature to postulate which 

 of these two conditions is a primitive one. 



Funnels. Spermatozoa are collected from the coelomic spaces of 

 the testicular segments by the modified ends of the efferent ducts, 

 which assume the general shape of a laboratory thistle-tube funnel — • 

 a subglobose enlargement, a subterminal constriction, and a slightly 

 flared free margin. The entire structure is composed of a single layer 

 of densel}'^ ciliated epithelial cells, and apparently varies in size and to 

 some extent in shape among different species and genera. Normally 

 the funnels are located in the lower posterior portion of the segments, 

 their openings directed dorsolaterad and easily detected by the 

 densely aggregated spermatozoa. Owing to the difficulty of obtaining 

 precise measurements from whole mounts, and the general similarity 

 of the funnels throughout the genus Cambarincola, their possible 

 taxonomic utility has not been carefully investigated. 



Efferent ducts. Each funnel is attached to a slender tubular 

 efferent duct, which proceeds ventromesad into the vicinity of the 

 bursa in segment vi. Here it unites with that of the opposed funnel, 

 forming the deferent duct. The efTerent ducts serving the funnels of 

 segment v penetrate the septum of segments v/vi near its ventral 

 margin, mesad to the funnels. Those confined to segment vi are to 

 be found in the ventral portion immediately caudad to the bursa. 



Deferent ducts. These conduits, formed by the union of a pair of 

 the smaller efferent ducts, are histologically similar to them but 

 average considerably larger in diameter. Originating in the general 

 region of the atrial portion of the bursa, the deferent ducts proceed 



