870 ME. W. F. LAXCHESTER ON THE [DeC. 2, 



B. atnaryllis, amphitrite, improoisits), I have been content to 

 follow him in this respect, aiid to consider ISTo. II. as a coloui'- 

 variety of No. I., the latter being then necessarily regarded as a 

 subspecies of B. amarylUs. For my jvistification in separating 

 this form from B. amarylUs, I must refer to the differences about 

 to be described. 



No. I. =the subspecies. 



This form agrees with B. amarylUs in all characteristics, whether 

 in structure of shell or structure of body, except those of the 

 opercular valves. These latter, although agreeing in general shape 

 with those of B ama.ryllis, present the. following differences : — 



(a) The scictum. — Articular ridge prominent, with a very slight 

 tendency to be reflexed to the tergal margin (this is better seen 

 in the large specimens of the subspecies than in the smaller speci- 

 mens of the variety) ; adductor crest prominent. These differ- 

 ences have been already noted by Dr. Weltner in his useful 

 Catalogue of recent Oirripede species {I. c. supra). 



(b) The tergum. — Depi-essor crests well developed ; spur, only 

 half its own width from the basiscutal angle. 



I think there is no doubt that, apart from No. II., these 

 differences would entitle No. I. to be considered as a vai'iety 

 of the species, and as such I should have classed it, did I not, 

 as I have said, follow Darwin in considering colour difference 

 of varietal worth, so that these differences must be considered as 

 subspecific. 



No. II. =var. clarovittata. 



Presents the same structural distinctions as the subspecies, and 

 differs in the shell being white with rather closely placed longi- 

 tudinal hyaline lines. 



In one specimen of this variety the basal margin of the tergum 

 is very concave between the spiu" and the basicarinal angle, while 

 the basiscutal angle is sharp, almost tooth-like ; and the basal 

 margin of the scutum presents a broad, shallow notch not far 

 from its basi-occludent angle. 



The large specimens are about 1| in. in gi^eatest diameter of 

 base, and about 1| in. high ; the small barely | in. across the 

 base, and g in. high. 



23. Balanus iENEAs, sp. nov. (Plate XXXIY. figs. 4-4 i.) 



Log. ? 



Shell white, smooth, not very tall, internally longitudinally 

 ribbed ; orifice toothed, but not deeply, large and rhomboidal. 

 Kadii reduced and very narrow ; basis porous, parietes solid. 

 Scutum with the lines of growth distant, not prominent ; articular 

 ridge prominent, extending about halfway down the tergal 

 margin ; adductor ridge not prominent. Tergum broad, without 

 any beak ; spur short, a quartei- of the width of the whole basal 

 margin, placed about two-thirds of its own width from the basi- 

 scutal angle, its apex rounded. 



