66 HERM^EID^l. 



azure or bluish-green spots of a metallic lustre : tentacles ear- 

 shaped, obtuse, dark green, frequently reflecting a purplish hue ; 

 the darker colour is frequently continued over the head and on 

 the upper and outer side of the lateral lobes of the body, which 

 are margined with white ; a whitish space surrounds each eye, 

 and the elevated region of the heart is also pale : the lateral 

 expansions rise up in a curved line towards the middle of the 

 back, and diminish gradually to the tail ; their inside is paler 

 than the out, and beautifully veined with green from the he- 

 patic vessels appearing through. L. 0*75. 



[Yar. olivacea. Dark greenish- or purplish-brown, spotted 

 with blue and red dots, the edges of the mantle and tips of the 

 tentacles being white.] 



HABITAT : On Codium tomentosum, Zostera marina, and 

 other green seaweeds, in tide-pools, or occasionally in shallow 

 water, especially on the south and west coasts. [The variety 

 inhabits Lochmaddy (M'Intosh) and Kiel Bay (Meyer and 

 Mobius). It does not appear to have been met with yet on 

 the east coast of England, though it has a wide range in 

 European seas, extending from Norway to the Mediterranean. 

 [Syn. Actceon minutum, Sars.] 



Suborder II. POLYBRANCHIATA. 



Gills, or, rather, branchial processes, arranged along the 

 sides of the body ; skin without spicula. 



Family I. HERM^'ID^E, Alder and Hancock. 



Without mantle : branchial processes linear or papillose : 

 tentacles 2, dorsal : vent dorsal : no jaws : hepatic system with 

 two longitudinal dorsal vessels. 



Genus I. ALDE'RIA*, Allman. 



BODY ovate : tentacles rudimentary or none : branchial pro- 

 cesses papillose, set in transverse rows on the sides of the back : 

 vent postero-dorsal, nipple-shaped : odontophore with a single 

 series of plates bearing a large central spine. 



* [Named in compliment to the author of this Synopsis.] 



