KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 39. N:o |. uy 
Ph. Sabellarix | Ph. improvisum . 
tt NlRbarsfarantlt oasen x | fare RR 
= SPC 0 Sr | Bm (0000 MH 3 5 
SRA 208 bl ET as 2 RSEO RO SS T 
SSE | Si eNebiea ÄAKeSdaN äg SET ck OMESNSN fl KEN Notes 
SAS) 1 ES STEN EAS SR ffa a | Eek ENN NES 
fre Str ICO ETEN SA = (4) ESO rn = sT 
fado 2208 ol Fille 5 &eV nov AO = 3 
NR? |fästef 230 | RR fire EA 
5 oe = bäva | & Se far FOR ESSEN 
EA SEEN ed ERE SET RENEE ue SRS 
= AD mus SE = INN ar ÖS ELIS 
s -— 3 - 2- 0 I 3 - RP OO 
I sp. | 48 S INS SA 17 | e Probably an abnormal individual of Ph. improvisum. 
ss = I 
2"sps. | 50 = I sp. 22 3 » » » » 
+ BD I = = I 
I = = > = 
1 sp. | 5l : I sp. 30 ant | 
- SA Ä =. I 
I sp. 2 = I sp. 32 | 2 | | 
S | D | 
3 SPS. ä3 = 1 sp. 30 | = | 
I I S F I I 
I SN I Iz 
I sp. Dö 2] 6 Sps. 40 = | 
E d I 
| &Ö = 
ISp:s | 6 = 5 Sps. 43 = 
2 | 2 f| Abnormal individuals with only one retractor-root 
I sp. 57 = 2 Sps. 46 | = | attached, in the one on the lett side of the nervee- 
5 | € 3 3 
= SS [| cord, in the other on the right. 
I sp. 58 TR 4 Sps. 48 R One individual has only the left retractor-root. 
1 sp. 62 = 2 Sps. 49 Zz | 
ST STO 
FET — - 4 Sps. 5 Zz | 
z P 5l : | 
c 5 = 2 
= — = 2 sps 15 5 | 
| 
[8 5 S | 
— — U I sp. 59 Så | | 
3 = N If One individual is in possession of onlv the left re- 
= = (= 2 Sps 61 S | ? 
e Il tractor root. 
-— - I sp. 67 a | 
sS = I 
== AA = | LS 179 z 
5 3 | LT TSE : : ; - 
= 2 5 [SS 95 : f Abnormal individual in possession of only the left 
ler 4 Il  retractor-root. 
From the table above it is evident that the length of the retractors, their attach- 
ment to the body-wall, and the degree of their coalescence are subject to rather 
considerable variations. This is strikingly obvious in Ph. improvisum, where the 
differences between the extreme forms are so enormous, that they doubtless should 
be considered as distinct species, did they not present series of transitiona] stages 
and did they not, besides, live close together, side by side, on the same shells and 
between the same sandy tubes of Sabellaria. Considering this, it lies very near to 
hand to assume that such a variation is also shown in other forms of Gephyrea and, 
consequently, that several species have been described as new, which in reality are 
nothing but varieties of already known ones. But it requires a great deal of material 
for drawing such comparisons and conclusions. As a matter of fact, I have had to 
work, in most cases, with a very scanty number of individuals of each species. 
With special regard to the extent of the coalescence of the two retractors, there 
seems to exist great differences in the same species. In Ph. improvisum the retractors 
have sometimes almost completely grown together, so as to form seemingly a single 
retractor, embracing the nervous cord with two very diminutive roots. In connection 
with this question the interesting fact ought not to be left out of sight, that among 39 
forms of Ph. improvisum there are no less than 5 individuals which are abnormal with 
regard to the retractors, proving that the deformities amount to a considerable per- 
E. Sv. Vet. Akad, Handl. Band 39, N:o 1, 10 
