284 Mr. II. G. Seeli'y on Zoocapsa dolicliorhainphia. 



The scutum is ibur-sidctl, as in Sculjiclhim, but wider from 

 the tero;al marp^iii to the occhidcnt margin along the straight 

 Lase than it is high from the l)asal margin to tlic apex. The 

 basal margin is slightly intlcctod. The oecludont margin, as 

 in Coronu/a, is moderately concave from base to apex, the 

 extremity of which is not exposed : in the living genera it is 

 straight or convex. This margin is destitute of the intlexion 

 so characteristic of recent sessile Cirripedes, and therein is 

 more like ScaljjeUuDi. The two remaining margins are 

 straight, make a large angle with each other ; and both join 

 the tergum. The upper margin, seemingly the longer of the 

 two, fits against the beak of the tergum ; the tergal margin 

 articulates with the tergum in the usual way. Extenuilly the 

 scutum was slightly convex and cancellate. The four-sided 

 form is clearly a consequence of the prolongation of the beak 

 of the tergum, and therefore no evidence of affinity, since the 

 margin, which here is properly tergal, in Scalpellum Avould be 

 lateral and be presented towards the u})])er latus. The species 

 of Balanus Avith a beaked tergum have the scutum only three- 

 sided, because the beak makes a slightly curved continuation 

 of the tergal margin, and not an angular bend in it. 



The tergum is an irregular, subtriangular, trilobed plate, 

 formed of three miequal triangular parts, whose apices termi- 

 nate with a long subcyliudrical apex of uniform Avidth, which 

 is bent slightly iuAvard so as to touch the scutum, when that 

 plate meets it at an angle, as is common among the Balanida?. 

 On the basal margin is a deep emargination in its middle 

 third, in the place wdiere the spur is developed in Balanus ; so 

 that in this respect it rather approximates to a species of 

 Elminius. This notch is at the termination of a wide depressed 

 groove, triangular in outline, forming the middle third of the 

 plate ; it widens toAvards the basal margin, as is characteristic 

 of the tergum in most of the Balanidaj. The third of the base 

 toAvards the carinal margin, hoAvcA'cr, is much prolonged ; it 

 Avidens, and is rounded at its termination. The carinal mar- 

 gin is straight, except just beloAV the origin of the apex, where 

 it Avidens so as to present a prominent angle. The scutal 

 margin is slightly inflected, much narroAver than in living 

 Balanij Avith the articulation formed by a very narroAV arti- 

 cular groove, margined on the outside by an equally narroAV 

 articuhir furrow, Avhich are adjacent to and extend the Avholc 

 length of the scutal margin up to the apex. 



Projecting from under the tergum is seen the greater part 

 of another (Jirri])cde plate. It is evidently not the other scu- 

 tum, being smaller, iior the other tergum, ni)r one of the com- 

 partments J yet, from its association Avith the valves described, 



