544 PROF. C. H. o'dONOGHUE : REPORT ON 
3.1.1.1.3); in the tenth row 81 {i. e., 39 . 1 . 1 . 1. 39), and in the sixteenth 
row about 273 (i. e., circa 135. 1.1.1. 135). When removed and flattened on 
the slide the radiila measured 11mm. along the middle line by 12 mm. at 
its widest point. The basal plate of the rachidial tooth is approximately 
rectangular, and the blade consists of three large spines, of which the 
median is the largest, the most pointed, and it projects well in front of the 
anterior margin of the basal plate. The lateral spines are blunt and much 
shorter. The first pleural tooth has a roughly rectangular base, but it is 
very irregular and it bears a singjle blunt and irregular spine. The remaining 
pleural teeth are all of a simple hamate form : they increase in size as they 
pass outwards, reaching their maximum between the 90th-120tb, and then 
they decrease rapidl}^ to the margin. 
Jaiv. The jaw, as is usual in the family, is very large and strong. Its 
most prominent feature is the series of serrations that mark its cutting-edge. 
They are quite small at the upper anterior end near the crista connectiva, 
where they first appear as the continuation of a wavy raised ridge, but 
they increase noticeably in size as they pass backwards. On the processus 
masticatorius they are quite large, nearly 1 mm. high and easily discernible 
with the naked eye. The denticles are deep brown in colour, and appear to 
be inserted into a lighter-coloured ridge. The well-developed jaws measure 
18 mm. long by 4'5 mm. at their widest point, and are of a deep horn-brown 
passing off almost to black near the cutting-edge. The}' are somewhat 
narrower than in other species of the genus, and perhaps more widely 
divergent at their posterior ends. 
The genital aperture is situated about halfway up on the right side near 
the level of the second bi-anchial plume. The penis is short, conical, and 
unarmed. 
The anal papilla lies just behind the third branchial plume, high up on 
the right side of the body. 
Notes. There are five specimens of this species in the collection : three 
with brown iiiottlings and two quite grey — none with closer localitj^ given 
than Abrolhos. 
However, it is almost certainly the animal referred to by Professor Dakin 
in his report (32, p. 170) as coming from Wooded Island*, since his remarks 
can apply to no other form in the collection, and the long branchife do give 
it a spurious resemblance io Dendronotus: He says, "Another animal which 
was extraordinarily abundant on this little stretch of Lagoon flat (only on 
the margin) was a large and beautiful nudibranch, almost certainly new 
and allied probably to Dendronotus. The singularity of its occurrence is 
accentuated by the fact that, notwithstanding its abundance here, not a 
specimen was captured anywhere else at the Abrolhos, and on our second 
visit in 1915 it was just as common at this place as two years before." 
* [This obsevvatiou is quite correct. — AV. J. D.] 
