DESCRIPTIONS OF GENERA AND SPECIES 681 



The clitellum in this worm has the same ridge that is seen in Bilimba papillata; 

 it extends over all the clitellar segments. There are no other copulatory structures. 

 HORST found that the alimentary canal contained a large quantity of Diatomaceae ; 

 hence it was inferred that the worm lived in the soil at the bottom of the lake in 

 which it was found. The species is not very fully described, and is not illustrated 

 by HORST in his paper. 



Genus HOBMOGASTER, ROSA. 



DEFINITION. Setae of dorsal series strictly paired, those of ventral series far apart ; 

 clitellar setae much larger than others, ornamented. Clitellum, XV-XXV. No 

 calciferous glands; three gizzards in VI, VII, VIII. Spermathecae in X, XI, 

 XII ; sperm-sacs, two pairs in XI, XII ; one pair of egg-sacs in XIV. 



This genus was apparently first described by REDI in the year 1684; two 

 centuries later it was re-described by ROSA (7). It has not been investigated by 

 any other naturalist. The genus only contains one species, hitherto only known 

 from Italy. The principal features in its structure are the following: 



The setae have the usual form of these organs ; but they are implanted in a 

 rather unusual fashion, except among the Eudrilidae ; the two setae of the ventral 

 couple are somewhat widely separated ; on the other hand, the two setae of each 

 dorsal couple are very close together. Upon the clitellum, as is usual in the 

 Geoscolicidae, the setae are different in character from those found elsewhere ; they 

 are here much longer and straighter and the free extremity is ornamented, though 

 apparently not in so marked a way as in such a genus as Pontoscolex. The 

 clitellum is but little prominent ; nor is it very distinct from the surrounding 

 segments by a difference of colour ; it extends from the fifteenth to the twenty-fifth 

 segment. The most abnormal external character of the genus is the position of the 

 male pores upon the border line between segments xv/xvi ; this place of opening is 

 found in but few other Geoscolicids and is so far an indication of affinity with the 

 Lumbricidae. BENHAM, indeed, is inclined to refer it to the family Lumbricidae. In 

 the digestive organs, the most noteworthy points are the presence of three gizzards 

 and the absence of calciferous glands ; there is no other member of the family in 

 which I place the genus in which there are three gizzards ; and as a rule (to which, 

 however, there are exceptions, such as Sipkonogaster) calciferous glands are to be 

 found ; the three gizzards of Hormogaster lie in segments vi, vii, and viii respectively ; 



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