of the Fishery Board for Scotland. 211 



joint; secondary branch small, one-jointed, arising from the middle of the 

 second joint, and hearing four slender apical setae. Mandibles stylet- 

 shaped, produced at the base into a barb-like process (fig. 28). Maxillae 

 two-branched, one branch stout, and bearing three apical spines and two 

 plumose setae, the other branch small, with three apical setae (fig. 29). 

 The first joint of the anterior foot-jaws stout, second joint elongate and 

 slender, and terminating in a moderately long curved claw and a small 

 spine (fig. 30). Posterior foot-jaw four-jointed ; second joint about three 

 times longer than broad, and bearing a small seta near the middle of the 

 inner margin ; third and fourth joints narrow, and together scarcely equal 

 in length to two-thirds of the second joint; terminal claw rather longer 

 than the two preceding joints, and provided with a small seta near the 

 middle of the inner margin. Both branches of the first pair of swimming 

 feet two-jointed, the second joint of the inner branch large and foliaceous 

 (fig. 32). 1 Third and fourth pairs somewhat similar to those of Licho- 

 molgus fucicolus, Brady ; slender, and with the marginal and terminal 

 spines of the outer branches broadly dagger-shaped (figs. 33, 34). Fifth 

 pair rudimentary, bilobed, with about three apical setae (fig. 35, a). Geni- 

 tal segment of the abdomen considerably dilated ; second and third seg- 

 ments short, and together scarcely equal in length to the first; last segment 

 equal to twice the length of the preceding one; caudal stylets rather 

 shorter than the last abdominal segment, furnished with five apical setae, 

 the second seta from the inside being considerably longer than the others, 

 and about equal in length to the last three abdominal segments. Ovisacs 

 two, large. 



This species has been known to us since 1889, but, because of some 

 uncertainty as to whether the first specimens obtained were mature, it 

 was considered expedient to defer recording it. A few months ago a 

 specimen with ovisacs was obtained, and quite recently several others, 

 also with ovisacs, have been secured. By the discovery of these speci- 

 mens our uncertainty as to the maturity of those previously obtained has 

 in a great measure been set at rest. 



Parartotrogus richardi resembles in some respects a curious parasitic 

 copepod, described by Sir John Dalyell in 1851* under the name of 

 Cancerilla tulndata, and which was discovered by him adhering to the 

 base of one of the arms of a species of Amphiura (a kind of starfish). 

 The same copepod has since been obtained on the coasts of France, and 

 is described and figured by Dr Canu in his work ' Les Copepodes du 

 ' Boulonnais.' But in Cancerilla the cephalo-thorax is greatly dilated, 

 the abdomen is very short, the anterior antennae are only six-jointed, and 

 the first pair of swimming feet are more rudimentary than in Pararto- 

 trogus ; and a further difference of considerable importance is, Cancerilla 

 has only been obtained as a parasite, whereas all the specimens of Parar- 

 totrogus that have yet been obtained were free. 



1 



Genus Bomol/chus, Nordman (1832). 

 Mikrograph. Beit, zur Naturg., II. Heft., s. 135-137. 



Animal somewhat like Lichomolgus in form. Anterior antennae 

 seven-jointed. Posterior antennae three-jointed. (?) Mandibles stylet- 

 shaped. Maxillae simple, the apex truncate, and provided with two 

 broadly ovate appendages. Foot-jaws rudimentary ; (?) anterior footjaw, 

 consisting of a simple stylet-shaped joint, bearing a single plumose seta. 

 Both branches of all the swimming feet three-jointed, first pair short, 

 foliaceous, furnished with spathulate and densely-plumose setae; the 

 * The Powers of the Creator, vol. i. p. 233, pi. lxii. figs. 1-5. 



