GENUS DINOPHYSIS. 459 



jugs ; adopting this simile, the inflated anterior portion is likened to the body of 

 the jug, the narrow discoidal part behind the annular furrow to the lid, and the 

 perpendicular membranous crest to the handle. 



Dinophysis atlantica, Ehr. 



Cuirass ovate, urceolate ; its surface densely shagreened, posterior 

 segment operculum-like, dilated, ventral plates with transverse decurrent 

 linear thickenings. Length 1-432". HAB. Salt water : Newfoundland. 



Excepting for its larger size this species is described by Ehrenberg * as correspond- 

 ing closely with Dinophysis Michaelis. 



Dinophysis acuta, Ehr. 



Cuirass ovate, acuminate posteriorly, the anterior margin plane, its 

 surface granulate. Length 1-576". 



HAB. Salt water : Baltic Sea, near Kiel (Ehr.). 



As originally figured and described by Ehrenberg, f the anterior and posterior 

 extremities have been reversed in both this and the succeeding species, D. Michaelis. 



Dinoflhysis Michaelis, Ehr. 



Cuirass ovate, rounded posteriorly, the anterior border plane, slightly 

 wider ; surface granulate. Length 1-576". 



HAB. Salt water : Baltic Sea, near Kiel (Ehr.). 



Dinophysis norvegica, C. & L. PL. XXV. FIG. 42. 



Body compressed, pitcher-shaped, rounded anteriorly, the posterior 

 segment reduced to a simple concave plate ; the dorsal and anterior margin 

 supplemented by a thin, longitudinally striate and sometimes denticulate, 

 keel-like crest, which tapers off on the ventral side towards the abrupt 

 termination of the raised ventral plates ; ventral plates strengthened by 

 three transverse linear thickenings ; surface of cuirass coarsely shagreened. 

 Length 1-400". HAB. Norwegian coast (Claparede & Lachmann). 



Dinophysis ventricosa, C. & L. 



Body compressed, pitcher-shaped, ventricose, the anterior extremity 

 frequently pointed, the posterior segment represented by a simple concave 

 plate ; no supplementary crest on the dorsal margin ; ventral plates with 

 three transverse linear thickenings ; surface of the cuirass coarsely 

 shagreened. Length 1-400". 



HAB. Salt water : Norwegian coast (C. & L.). 



Dinophysis acuminata, C. & L. PL. XXV. FIG. 43. 



Body compressed, pitcher-shaped, rounded anteriorly, more considerably 

 inflated on the dorsal side, supplemented at the antero-ventral angle with 



* ' Monatsbericht Berliner Akademie,' 1854. 

 t ' Abhandl. d. Akad. Berlin,' 1839 and 1840. 



