ASHWORTH, AN ACCOUNT OF ARENICOLA LOVENI KINBERG. 11 



specimens tlie first gill is small, in one of the Saldanha 

 examples the first left gill is represented by a minute tri- 

 lobed tubercle. The successive gills increase gradually in size 

 up to about the tenth, which is usually the largest; the last 

 gill is distinctly smaller than the preceding one. 



In those specimens in which the gills are well expanded 

 they are seen to be of the pinnate type as is clearly indica- 

 ted in Kinberg's figures 1 A, IF. The larger gills of the type 

 specimen consist of sixteen to twenty axes on each of which 

 lateral branches are borne. The longest axes of the middle 

 gills are 7 mm. in length and bear about sixteen branches 

 on each side. The gills of the Saldanha specimens are of 

 exactly the same type. The ninth right gill of one of them 

 was exarained in detail; it consists of nineteen axes connec- 

 ted by a short common basal piece less than 2 mm. in length; 

 there is no well marked web-like membrane between the bases 

 of the gill axes of this species such as is often present in 

 large Laminarian specimens of A. marina. The longest axis 

 of this gill is about 7 mm. in length and bears on each side 

 fifteen branches; the shortest axis is rather less than 3 mm. 

 in length and has six pairs of lateral branches. ^ The lateral 

 branches, though often opposite or paired, are not always 

 so arranged, on some axes or on some portion of certain axes 

 they are alternate. The subsequent branching of the lateral 

 twigs is either dichotomous, or, especially in the larger ones, 

 approximately pinnate. 



Internal orgrans. 



(Fig. 7). 



The internal organs of the type specimen and of two of 

 the Saldanha examples have been examined. 



Septa and miiscles. 



The three septa, present in all known species of Areni- 

 cola, are found in A. loveni in the usual positions, namely, 

 at the anterior end of the first, third and fourth chaetige- 

 rous segments. 



^ A gill axis, intermediate between these in length and number of 

 branches, is seen in Fig. 2. 



