of the Fishery Board for Scotland. 



247 



apparently imperfect as regards the furcal hairs, and no doubt helped to 

 disguise their relationship with the species named. Having now obtained 

 specimens in fairly good condition, I am enabled to give a few accurate 

 figures of the female which may be of interest as supplementing Dr. 

 Bourne's very fine drawings of the male, (See the Quarterly Journ. of 

 Micros. Science, vol. xxx., pt. 4, new series, Feb. 1890.) 



Monstrilla dubia, T. Scott, sp. n. PI. xiii., fig. 14 ; pi. xiv., fig. 16-18. 



Description of the Female. — Body moderately slender ; length of the 

 specimen represented by the drawing is 33 mm. (fully g of an inch). 

 The cephalothoracic segment is about one and a half times the entire 

 length of the remaining thoracic segments and abdomen. 



The abdomen is composed of three segments ; the first segment is about 

 equal in size to the last segment of the thorax, the second is smaller than 

 the next, while the second and third are together scarcely as long as the 

 first segment (fig. 14, pi. xiv.). 



The antennules are moderately stout and about half as long as the 

 cephalothoracic segment, and composed of four joints ; the first and third 

 joints are small, the second is about half as long again as the third, while 

 the fourth is equal to the entire length of the three joints (fig, 16, pi. xiv.) 



The fifth pair of thoracic feet are moderately slender ; each foot is 

 narrow and sub-cylindrical at the proximal end, but becomes wider 

 distally and terminates in two lobes ; the outer lobe is larger than the 

 inner and is furnished with three moderately long setae, the inner lobe is 

 narrow and appears to be devoid of setae as shown in the drawing (fig. 

 17, pi. xiv.). 



The furcal joints are each provided with four elongated hairs, one of 

 them springs from near the base of the outer margin, two spring from 

 the apex, while the fourth is attached on the inner aspect and near the 

 middle of the joint, as seen in the drawing (fig. 18, pi. xiv.). 



Habitat. — Firth of Forth, east of Inchkeith, August 14, 1891 ; and 

 head of Lech Fyne (Firth of Clyde), November 11, 1897, and November 

 28, 1899. No males have been observed. 



Remarks. — The Copepod of which I have just given a description 

 does not agree with any described species known to me. The characters 

 by which it may be distinguished are the following three : first, the 

 structure of the abdomen, the first segment of which is as large as the 

 segment of the thorax next to it ; second, the peculiar form of the fifth 

 pair of thoracic feet ; and, third, the number and arrangement of the 

 furcal setae. 



Monstrilla dubia as described and figured here has a somewhat close 

 resemblance to the female of M. danw as represented by the beautiful 

 drawings of Professor Claparede,* and especially by figure 3, taf. xvi., 

 which shows the female from the under side ; the proportional lengths of 

 the abdominal and of the posterior thoracic segments are almost identical, 

 but the furcal joints are represented with only three setae ; there is also 

 a slight difference in the length of the second joint of the antennules. 

 Had a separate drawing of the fifth pair of thoracic feet of the female 

 been given by that author the identification of the species would have 

 been rendered more certain. 



* Beobachtungen uber Anatomie und Entwicklungsgeschichte wirbelloser thier an der 

 kiiste von Normandie, AngestelU, p. 95, taf. xvi., fig. 1-6 (1863). 



