156 SIR w. A. HERDMAN : RESULTS OF CONTINUOUS 
follows :— * I must admit that T cannot find any transition from B. sinensis 
to D. regia, or vice versa. When I got your Report for 1912 and looked 
thoroughly at the photos of Pl. I., T got at once the impression that figs. 1-15 
were all B. sinensis, figs. 16-19 B. regia. This impression has been verified 
by examination of the sample. I have seen specimens of B. sinensis with 
supernumerary spines, specimens resembling fig. 5, and a few specimens 
resembling figs. 7-9, but I have not seen any real transitional stage to 
B. regia, all the deviation being, in my opinion, only abnormal (teratological) 
stages of B. sinensis. It seems to me that while B. regia is vigorous and 
healthy in the Irish Sea, B. sinensis is disposed to producing anomalies, most 
probably because the conditions of life are in some way or other not favour- 
able for its development. After having examined this sample I feel still as 
much convinced of the independence and stability of the species B. sinensis 
as I felt before.” 
The opinion of such a distinguished authority as Prof. Ostenfeld must 
have great weight, but it must be remembered when considering these 
abnormal forms of Biddulphia that other similar cases of apparent transi- 
tions between species are known amongst diatoms, such as that of the arctic 
Rhizosolenia hebetata and our common Atlantic form R. semispina discussed 
by Gran *, 
The less prominent and less well-known diatoms Lauderia borealis and 
Guinardia flaccida occasionally appear in large numbers and reach millions for 
a short time. Lauderia occurs along with Chetoceras in late April or May and 
Guinardia along with Rhizosolenia in June, so they help to swell the carlier 
and the later crests respectively of the spring diatom curve. Lauderia, for 
example, amounted to over 20 millions on April 22nd, 1910, and to 
12} millions on April 29th, 1912; and Guinardia to 18 millions on May 30th, 
and nearly 23 millions on June 3rd, 1912. 
Asterionella is another form which on rare occasions runs up to very high 
numbers. The species A. Bleakeleyi is frequently present in small quantities, 
but in 1913 A. japonica appeared in enormous numbers for quite a short 
period in the middle of May and reached 192 millions in one haul on 
May 16th. Two months before and two months later none were present. 
DINOFLAGELLATA. 
The Dinoflagellate maximum in summer usually follows that of the 
diatoms, but is not nearly such a marked increase. In the 15 years 
recorded it has ranged from May to August, but has most frequently been 
in July. Some years, such as 1908, 712, '18, and 720, have been much 
more favourable than the rest, and in 1907, '9, and ’17 the dinoflagellates 
were rather poorly represented. The favourable years are not always (1908) 
* See Murray and Hjort, ‘The Depths of the Ocean,’ p. 320. 
