224 MR. F. E. BEDDABD 0>' NEW EAETHWOBMS. [Mar. 19, 



penial setae are long for the size of the worm and also slender. 

 They are curved in the usual way and terminate in a very pointed 

 extremity. The setae are not ornamented. The spermathecae are 

 tubular in shape and have a tubular diverticulum of equal length. 

 Rah. St. 47, Corral, " Wald, unter Steinen." 



Genus Kerria, Beddard. 



The collection contained examples of at least three species of this 

 genus, of which I regard two as new. The species which is not 

 new is Kosa's Acanthodrilus spegazzinii. I have before expressed 

 the opinion that this species is really a member of the genus Kerria. 

 I am now in a position to confirm that supposition. The genus 

 is at present chiefly known from an excellent paper by Eisen upon 

 new species which he discovered in California. 



The existence of this paper renders it necessary for me to enter 

 into the minute anatomy of the species, to which I refer, or which 

 I describe, for the first time in the present paper. The genus 

 is, so far as we know at the present time, exclusively American. 

 It also appears to be a tropical genus, or at least to be a 

 native of the warmer parts of the American continent. The 

 original species of the genus, Rosa's '■^Acanthodrilus" sjiegazzinii, 

 was met with in the neighbourhood of Buenos Ayres ; my species 

 Kerria halophila was brought back by Mr. Graham Kerr from the 

 upper reaches of the Pilcomayo River. The new species which I 

 describe in the present paper were found at Buenos Ayres 

 and in Valdivia. Eisen's species were found by him in Lower 

 California. The two northern species of the genus diiFer from 

 the southern species in having no gizzard and in having diverticula 

 of the spermathecae. 



(1) Kerria rosae, n. sp. 



Eisen has used as a character for distinguishing the different 

 species of this genus the number of setae present upon the seg- 

 ments which bear the pores of the sperm-ducts and of the 

 spermiducal glands. This character is probably valuable, but it 

 must be used with circumspection. In two examples of the 

 present species the setae upon the segments in question differed. 

 In one individual they were all present ; in another the inner of 

 the two ventral setae was alone present on segments xvii. -xix., 

 excepting on one side of one segment, where the outer seta alone 

 was present. There is no doubt that this difference has some 

 relation to the condition of the maturity of the worm, but the 

 same remark may possibly apply to other cases. 



The species to which these observations apply is a longish, thin 

 worm, rather more than an inch in length and about 1 mm. 

 in breadth. A large number of specimens were collected under 

 stones on the banks of the river Baraccas do Sul near Buenos 

 Ayres. The species is described by Michaelsen as having been 

 " flesh-red " during life ; none had a clitellum. 



