160 



Part III. — Eighteenth Annual Report 



length of genital segment, 8mm. ; length from forehead to end of ovisacs, 

 23mm. 



Glavella hippoglossi has well developed and moderately stout five-jointed 

 antennules, which are sparingly setiferous (fig. 2). The antennae are 

 moderately large and provided with powerful terminal hooks suitable for 

 grasping (fig. 3). The mandibles are small, elongated and tapering, and 

 armed with a few small teeth at the distal end of the inner margin. The 

 niaxillse, or palpi, are very small, but comparatively stout, and are 

 provided with two or three special tooth-like processes. The foot-jaws are 

 elongated and slender. Both pairs of the thoracic feet are two- branched 

 and both branches appear to be two- jointed (fig. 6). No males have been 

 observed. 



Genus Cycnus, M. -Edwards (1840). 

 Syn. Congericola, Van Beneden (1854). 



The species belonging to Cycnus are in general appearance somewhat 

 similar to Clavella ; they may be distinguished, however, by the possession 

 of four pairs of two-branched thoracic feet, instead of only two pairs, but 

 these thoracic feet are not so fully developed as in Clavella. I have only 

 observed one species of Cycnus, viz. : — 



Cycnus pallidus (Van Beneden). 



1854. Congericola pallidus, Van Ben., Bull. Acad. Eoy. Belg , vol. 



21, pt. ii., p. 583. 

 1896. Cycnus pallidus, Basset-Smith, Journ. M. B. Assoc. (Feb. 



1896), p. 159. 



About 30 specimens, counting adult, immature and damaged, of this 

 species were obtained on the gills of a large Conger vulgaris sent from 

 the Clyde by Mr. F. G. Pearcey, naturalist on board the " Garland." The 

 conger was captured at Station IX., near the mouth of the estuary, on 

 December 13th, 1899. In form and colour these parasites closely 

 resemble pieces of the gill-filaments, and may therefore be readily over- 

 looked. The specimens I observed were found to adhere very firmly to 

 the gill-filaments, so much so that several specimens were damaged in the 

 course of removing them. 



None of the specimens measured reached to quite four millimetres ; one 

 specimen was about 3*7mm. in length, exclusive of ovisacs, and from the 

 forehead to the end of the ovisacs the length was 8 '2mm.; another 

 specimen, measured in the same way, reached to 3 # 8mm. and 9 , 3mrn. 

 respectively ; the same specimens measured about '7mm. in width. 



Fam. LERNiEID^E. 



This family appears to contain a strangely mixed lot of parasitic 

 copepods. The adult females belonging to some of the genera in this 

 group have a somewhat abnormal appearance ; development in their case 

 is retrogressive, and to such an extent that in some instances nearly all 

 traces of the characters which distinguish these copepods from the other 

 orders of Crustacea are obliterated. Lerncea branchialis may be cited as 

 an example of extreme degradation. On the other hand, there are some 

 species which have rather an elegant shape and possess copepod characters 

 of a more distinctive form. 



Three genera of the Lemaiidm are represented in the present paper. 



Genus Lernaiemcus, Lesueur. (1824). 

 Syn. Lerneonema, M.-Edw. (1840). 



